Decode video in Raspberry Pi without using OpenMAX?

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遇见更好的自我
遇见更好的自我 2021-02-12 20:21

I am looking for an example of decoding video on Raspberry Pi directly, without using OpenMAX.

This explains the different layers of multimedia software:

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  •  情深已故
    2021-02-12 21:03

    I don't have a working example, but I have an API walkthrough. Sort of..

    Link to the full source code

    I found the following function that demonstrate how you can call vchiq_bulk_transmit

    int32_t vchi_bulk_queue_transmit(VCHI_SERVICE_HANDLE_T handle,
        void *data_src,
        uint32_t data_size,
        VCHI_FLAGS_T flags,
        void *bulk_handle)
    {
        SHIM_SERVICE_T *service = (SHIM_SERVICE_T *)handle;
        ..
        status = vchiq_bulk_transmit(service->handle, data_src,
            data_size, bulk_handle, mode);
        ..
        return vchiq_status_to_vchi(status);
    }
    EXPORT_SYMBOL(vchi_bulk_queue_transmit);
    

    There is a function to create VCHI_SERVICE_HANDLE_T

    int32_t vchi_service_create(VCHI_INSTANCE_T instance_handle,
        SERVICE_CREATION_T *setup,
        VCHI_SERVICE_HANDLE_T *handle)
    {
        VCHIQ_INSTANCE_T instance = (VCHIQ_INSTANCE_T)instance_handle;
        SHIM_SERVICE_T *service = service_alloc(instance, setup);
    
        *handle = (VCHI_SERVICE_HANDLE_T)service;
        ..
        return (service != NULL) ? 0 : -1;
    }
    EXPORT_SYMBOL(vchi_service_create);
    

    But you need a VCHI_INSTANCE_T which can be initialized here

    int32_t vchi_initialise(VCHI_INSTANCE_T *instance_handle)
    {
        VCHIQ_INSTANCE_T instance;
        VCHIQ_STATUS_T status;
    
        status = vchiq_initialise(&instance);
    
        *instance_handle = (VCHI_INSTANCE_T)instance;
    
        return vchiq_status_to_vchi(status);
    }
    EXPORT_SYMBOL(vchi_initialise);
    

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